Apparatus for classifying granular material



Dec. 2, 1924. 1,517,509

M. HOKANSON APPARATUS FOR CLASSIFYING GRANULAR MATERIAL Filed March 4,1922 2 Sheets-Sheet 1 10 W I 22 J Dec. 2, 1924- 1,517,509 M. HOKANSONAPPARATUS FOR CLASSIFYING GRANULAR MATERIAL Filed March 1 2 Shee.s-Shee!2 I H L WITNESSESS INVENTOR M g ATTORNEYS Patented Dec, '2, 1924.

UNITED/STATES PATENT OFFICE.

-MARTI1I HOKANSON, OF DULUTH, MINNESOTA APPARATUS FOR CLASSIFYINGGRANULAR MATERIAL.

Application filed March 4, 1922. Serial No. 541,168.

To all whom it may concern:

Be it known that I, MARTIN HOKANSON, a citizen of the United States, anda resident of Duluth, State of Minnesota, have invented a new and usefulImprovement in Apparatus for Classifying Granular Mate.- ial, of whichthe following is a specification.

This invention relatesto an apparatus for classifying granular materialand has for an object the rovision of a device that will readily .andeciently effect a separation of the particles comprising a granularmaterial into grades or classes according to their respectlve sizes.

Although the device is adapted for general use wherever it is desirableto effect a se aration or classification. according to t e size of theparticles comprising the material, it is particularly adapted andintended for use in connection with the separation of the valuable partsof ore from gangue.

It is .a special object to providea device for effecting the desiredpurpose without the use of screens or shaking tables, in which theseparation is produced by utilizing the greater rolling action of thelarger particles, in which the material is operated u on while in theform of a thin sheet where y the induced rolling action will eflect asharp and clean separation of the particles, in which the path of therolling particles will be of considerable length without necessitatingparts of cumbersome pro ortions, in whic the rolling action is a,pos1tively induced one and which can be easily varied to suit varyingconditions, and in which means are employed to enhance the effectivenessof the rolling action of the larger particles by preventing or hinderingthe rolling actlon of the smaller particles of the material.

It is also an object to provide a device possessing a large capacity ofproduction without detracting from its efiiective operation to produce asharp separation, which is of simple construction, easy to operate andrepair, and which can be economically manufactured.

These and other objects of the invention will more readily appear whentaken in connection with the following description and the appendedclaims.

In the accompanying drawings, Fig. 1 is a diagrammatic view with partsin section illustrating one embodiment of the invention; Fig. 2 afragmentary view of a modified form; and Fig. 3 a transverse sectortaken on line IIIIII of Fig. 2.

The embodiment of the invention shown in Fig. 1 comprises a supportinframework consisting of the upright mem ers 1, only two of which areshown, and transverse members 2, said framework resting upon a suitablefoundation 3.

Suspended in any desirable way between the upright members 1, andconcentrically arranged, are a plurality of annular funnel .shapedcollectin compartments 4, 5 and 6 having inclined ottoms and equippedwith the discharge chutes 7 8 and 9 respectively. The several annularcompartments are suitably connected and spaced apart at intervals bymeans of vertical sheet separators of well known construction,-thoseadjacent the top portions being indicated at 10 and those nearer thebottom at 11, the assembled compartments being suspended as a unit byattaching the exterior wall of the outer compartment. 6 to the upright 1at 12. These compartments may be constructed of any suitable material,preferably of metal, and the space between the inner com artment 4 formsa chamber which is closed loy a top 13 having at its center a bearing14:. A spider 15 mounted in this chamber also carries a bearing 16aligned with bearing 14 in which a shaft 17 is journaled, said shaftextending through a tubular prolongation 18 projectin downwardly fromthe chamber.

The tu ular extension 18 serves as an inner wall for the lower end ofcompartment 4 and also as a housing for the shaft 17.

Shaft 17 is centered and supported by a foot bearin 19, and attachedthereto adjacent the cot bearing is a driving pulley 20 adapted to bedriven from any suitable source of power by means of the belt 21.

Attached to the upper end of shaft '17 and disposed immediately abovethe top 13 is a circular distributingdisk or table 22.

The upper surface of the disk is preferably conical center exposed withthe covering extending within a short distance therefrom to theperipheral edge of the disk, or a two part covering ma be employedhaving the central portion 0 a material possessing the necessarywear-resisting qualities. The upper surface of the disk or table 23 issomewhat higher at its central point in order to distribute the materialevenly from which it preferably slopes downwardly along a curved path toits intermediate portion and thence curves upwardly to its periphery,the edge of which is rounded as shown. This rounded edge is of specialutility when the material operated upon is mixed with water, in a mannerto be presently described, due to the greater surface tension betweenthe water and the table than between the water and the particles ofmaterial carried thereby.

The material to be treated is fed upon the table 22 at its center 24from an agitating hopper 25 suspended at 26 in the transverse members 2,is deposited upon the table at a low velocity, and due to the conicalshape of the center of the table it will immediately spread out in theform of a thin sheet. This discharge mouth 27 of the hopper is disposeddirectly over the center of the table and at a very short distancetherefrom, and is provided with a regulating valve 28 towards which thefunnel shaped bottom of the hopper gradually slopes.

The feed hopper may be filled in any de sired manner. The embodimentsillustrated are particularly intended for use in connection withmixtures of ores and gangue which are introduced through a conduit 29controlled by gate valve 30, while the supply of water with which it ismixed is introduced by means of pipe 31 rovided with a valve 32. Mountedwithin t e hopper is an agitator consisting of shaft 33, carrying wingsor blades 33, journaled in bearings 34 and 35 supported by spiders 36and 37, respectively. Attached to the upper extremity of shaft 33 is abevel pinion 37 meshing with a second bevel pinion 38 fixed to a shaft39 driven from any suitable source of power. By such means the ore andwater can be thoroughly mixed to separate the particles from each otherand to maintain the mixture in a uniform condition.

In use, if dry material is operated upon, the granular material isdeposited from the hopper at a low velocity, and in such quantity as toinsure its being spread out in the form of a thin sheet upon therotating table or disk 22 by the time it reaches the lowest depressionon the table. the difl'erences in sliding and rolling friction betweenthe particles and the supporting surface of the table, and to the factthat the larger particles more easily acquire a rollgether.

Due to ing motion under the influence of the several impelling forces, arolling action is immediately induced in the larger particles, thelineal velocity of which gradually increases as said particles approachthe peripheral edge of the tablc,. the final velocities obtained varyingin accordance with their relative sizes. The smaller particlesconsequently do not tend to roll easily relatively to the largerparticles and under practical operating conditions, do not attain but asmall velocity relative to the larger particles as a result of theirrolling motion.

Due to the above described action it is obvious that by the time theseveral particles reach the peripheral edge of the table, the largestparticles have assumed a high velocity away from said edge, and thesmallest particles a comparatively low velocity, while the particles ofintermediate size acquire a velocity therebetween. The largest particlesare therefore projected the greatest distance from the table and arecaught. in the outer annular compartment 6, the smallest particles fallinto the inner compartment 4, and those of intermediate size arecollected by the middle compartment 5.

In the embodiments illustrated only three compartments are used whichseparate the particles into but three grades. The same principle ofseparation applies, however, rcgardless of the number of collectingcompartments employed, so that by varying the number of saidcompartments the number of grades into which the particles are separatedmay be varied at will.

Although a similar separation is efl'ected by using a table of the formshown without a covering of material, such as rubber or canvas, thedifference between the rolling motion induced in the large and smallparticles with the consequent difference in their final velocities isgreatly enhanced by its use.

The operation so far described has had reference especially to thetreatment of materials in a dry condition in which the several particlesdo not cling tightly to- It is impossible to effect a clean separationof certain materials due to their normally moist condition or because ofthe presence of substances which act as binders to cause the particlesto stick to each other. If the materials are thoroughly mixed with waterso as to free theparticles from each other and this mixture fed, asabove described, upon the table, and allowed to spread out in the formof a thin sheet, the separation will not only take place in the mannerset forth but will be more pronounced. This results apparent- 1y fromthe fact that the rolling action of the larger particles are practically12nafi'ected by the presence of the sheet of Water on the table.while-the smaller parti- Ill) cles are submerged to a greater or lessexv crease in the diflerence in the final velocities assumed by thevarying sized particles with a consequent. sharp separation into. gradesor classes. a

The preferred contour of the upper surface of the table has beenillustrated in which the travel of the material during its initialmovement from the center thereof is in a downwardly curved path underthe combined action of centrifugal force and gravity, and as itapproaches the edge of the table is in a path curved upwardly over whichit moves under the action of centrifugal force. The exact form shown ismerely illustrative and may be varied to meet varying conditions ofoperation necessitated by changes in the material handled and itsrelative characteristics, but

is so designed as to cause a positive rolling action of the materialuntil it'actually leaves the edgeof the table. It is obvious that theexact form of the table depends also upon the speed. at which the tableis rotated, and that for the same form of ta ble a comparatively widerange of control may be secured by suitably regulating its speed ofrotation to change the centrifugal force tending to move material beingtreated.

While the device is adapted to effect a separation according to size ofparticles of granular material generally, the form illustrated isprimarily intended and designed to effect a separation of the largerparticles of gangue from the smaller particles of ore in a mixture ofores and gangue, and is particularly useful in segregating the gangueand ore particles after a preliminary classification has been effectedto obtain a mixture containing gangue and ore particles which will besuspended in equilibrium by the same vertically upwardly flowing streamof water. A classification to procure such a mixture may be effected byany method or device, such as by feeding an ore containing gangue,substantially different in specific gravity, to devices such asdisclosed in my previously filed applications, Serial No.

,245,296, filed July 17, 1918, and Serial No. 272,327, filed January 21,1919, details of which, however, are not necessary to an understandingof the present invention. By such devices a mixture of gangue and .oreparticles is secured in which the size of the gangue particles varywithin cer tain limitsand in which the ore particles also vary withincertain limits, but all of which willbe suspended in equilibrium by thesame vertically flowing stream of water. [As an example of such a gradedor classified mixture, one containing silica tite particles ranging from.1 to .04 inch in diameter might be given. If the-mate- ;rial of theexample just given mixed with water is fed upon the rotating table, thesilica particles because of their greater size will be ejected from thetable at a decidedly greater velocity than the hematite particles whichare of smaller size. Consequently, if the velocity of the table isproperly regulated substantially all the silica particles will fallinto,the outermost compartment 6 and if the other compartments are ofproper width substantially all the ore particles will drop into theinner compartment 4. Due to the fact that the smallest silica particlesare of substantially the same size as the largest hematite particles, acertain number of silica and hematite particles because of theircorresponding size will attain substantially the same velocity. Theseparticles are caught by the intermediate compartment 5 and can besubsequently treated in any of the well known ways to effect aseparation due to the difference in specific gravities of the twomaterials. Applicants separator therefore possesses particular utilityin the concentration of ores of the character named.

As above stated, and with the material taken as an example, theparticles which fall into the intermediate chamber 5 are partly hematiteand partly silica, all particles however being of substantially the same'size. The particles of silica are therefore considerably li hter thanthe particles of hematite. if a blast of air of suitable intensity isforced upwardly through the chamber 5, the lighter particles of. silicawill be deflected upwardly without appreciably affecting the path oftravel of the heavier particles of hematite. By properly regulating thisupward blast, it is obvious that a very largev number of the silicaparticles can be made to pass over into the outer compartment 6 reducing'those falling into the intermediate compartment to a minimum, therebyeffecting a. decidedlycleaner and sharper separation. In F igs. 2 and 3is illustrated a modified form of device utilizing the upwardly flowingair blast in the intermediate compartment.

In this modifiedform, an annular chamber 40 surrounds the lower reducedextremity of compartment 5 to which air under pressure is suppliedthrough the pipe 41 having the interposed control valve 42-. The chamber40 is placed into communication with the interior of the compartmentby aseries of equally spaced apertures 43 extending through the wall of thecompartment. In order to prevent the escape of air downwardly throughthe outlet 8, the same is provided with a water seal by directingparticles ranging from .25 to .1 and hemasaid outlet below the surfaceof water contained within a vat, as indicated at 44.

From the above description, the mode of operation of this form isobvious. The valve 42 is opened to an extent to admita sufficientquantity of air to cause an upward blast through the compartment 5 whichwill deflect the lighter silica particles causing them to travel overinto the outer compartment while retaining theheavier hematite particleswithin the intermediate compartment, otherwise operating in identicallythe same manner as the form previously described.

It is thus seen that the invention provides a device for separatinggranular materials composed of various sized particles, which is simplein construction, easy to operate, economical to manufacture, void of allscreens or shaking tables, and while adapted for general useis'particularly useful in the concentration of ores or for similarpurposes.

I claim:.

1. An apparatus for grading granular material according to the size ofthe particles composing the same, comprising a laterally extendingdistributing disc or table having its entire upperplain surface exposedand operative to retard sliding movement of said particles and to inducerolling action thereof, means for rotating the disc, and means forseparately collecting the different sized particles dischargedtherefrom.

2., An apparatus for grading granular material according to'the size ofthe particles composing the same, comprising a lat erally extendingdistributing disk or table having its entire upper plain surface freelyexposed and provided with a covering hindering the free sliding actionbut inducing rolling action of the particles, means for rotating thedisk, and means for separately collecting the different sized particlesdischarged therefrom.

material according to the size of the particles composing the same,comprising a distributing disk having its upper face unobstructed andfreely exposed throughout its entire extent, means on said disk forenhancing the rolling action of the particles, means for rotating thedisk, and means for separately collecting the different sized par ticlesdischarged therefrom.

4. An apparatus for grading granular material according to the size ofthe particles composing the same, comprising a distributing disk, theupper freely exposed plain surface of which is unobstructed throughoutits entire extent and slopes gradually downwardly from its centralportion to a point intermediate its center and peripheral edge andthence upwardly to the said edge whereby to increase the rolling actionof the particles, means for rotating the disk, and means for separatelycollecting the different sized particles discharged therefrom.

5. An apparatus for grading granular material according to the size ofthe particles composing the same, comprising a distributing disk, theupper surface of which slopes gradually downwardly from its centralportion to a point intermediate its center and peripheral edge andthence upwardly to the said edge whereby to increase the rolling actionof the particles, the said peripheral edge being rounded, means for-rotating the disk, and means for separately collecting the differentsized particles discharged therefrom.

6. An apparatus for grading granular material according to the size ofthe particles composing the same, comprising a dis tributing disk havingits upper face unobstructed and freely exposed throughout its entireextent, a covering on the said disk for enhancing the rolling action ofthe particles, means for rotating the disk, and means for separatelycollecting the different sized particles discharged therefrom.

7. An apparatus for grading granular material according to the size ofthe particles composing the same, comprising a distributing disk theupper surface of which slopes gradually downwardly from its centralportion to a point intermediate its cen ter and outer edge and thenceupwardly in an unbroken curve to the said edge, and a covering on saiddisk whereby to increase the rolling action of the particles, means forrotating the'disk, and means for separately collecting the differentsized particles discharged therefrom.

8. An apparatus for grading granular material accordin to the size ofthe particles composing the same, comprising a distributing disk havingitsupper face unobstructed and freely exposed throughout 3. An apparatusfor grading granular its entire extent, a rubber covering on said diskfor enhancing the rolling action of the' particles, means for rotatingthe disk, and a plurality of concentrically arranged compartments spacedfrom the disk for separately collecting the particles of varying sizedischarged therefrom.

9. An apparatus for grading granular material according to the size ofthe particles composing the same, comprising a distributing disk havingits upper face unobstructed and freely exposed through its entireextent, the upper surface of which gradually slopes downwardly from itscentral portion to a point intermediate its center and peripheral edgeand thence upwardly in an unbroken curve to the said edge, and a rubbercovering on said disk whereby to increase the rolling action of thepartiunobstructed and freely expose cles, means for rotating the disk,and a plurality of concentrically arranged compartments spaced from thedisk for separately collecting the particles of-varying size dischargedtherefrom. 1

10. An apparatus for grading granular material according to the size ofthe particles composing the same, comprising a distributing disc havinga plain u persurface d throughout its entire extent and operative toretard sliding movement of the said particles and to induce rollingaction thereof, means for feeding the material upon the disc in the formof a thin sheet, means'for rotating the disc, and a plurality ofconcentrically arranged annular compartments spaced at differentdistances from the periphery of the disc for separately collecting theparticles of varying size discharged therefrom. '11. An' apparatus forgrading granular material according to the size of the particlescomposing the same, comprising a distributing disk having a plain uppersurface unobstructed and freely exposed throughout its entire extent,means for feeding the material on the disk in the form of a thin sheet,the upper surface of the disk sloping downwardly from its centralportion to a point intermediate its center and peripheral edge andthence upward" ly in an unbroken curve to the said edge whereby toincrease the ro lling-j action of the particles, means for rotating" thedisk,

- and a plurality of concentrically" arranged annular compartmentsspaced at different distances from the periphery of the disk forseparately collecting the particles of varying size dischargedtherefrom. j

12. An apparatus for I grading granular material, according to the sizeof the particles composing the same, comprising a distributing diskhaving its upper surface unobstructed and freely exposed throughoutitsentire extent for enhancing the rolling action of the particlesdeposited on the disk, means for rotating the disk, a plurality ofconcentrically arranged compartments spaced from the disk for separatelycollecting the particles of varying size discharged from the disk, andmeans for directing a blast. of air upwardly through an intermediatecompartment for upwardly deflecting the lighter particles passingtherethrough.

.13. An apparatus for grading granular material, according to the sizeof the particles composing the same, comprising a distributing diskhaving its upper surface unobstructed and freely exposed throughout itsentire extent, a covering thereon ofiering high frictional resistance tosliding movement of the particles deposited thereon whereby to inducerolling action thereof, means for rotating the disk, a plurality ofconcentric annular compartments spaced from the disk, and means fordirecting a regulated blast upwardly through an intermediate compartmentfor deflecting the lighter particles passing therethrough.

14. Apparatus for grading granular material according to the size of theparticles composing the same, comprising a distribut' ing disk havingits upper surface unobstructed and freely exposed throughout its entireextent and so shaped as to' induce a rolling action to the particles,means for rotating the disk, a plurality of concentrically arrangedcompartments spaced from the disk, and means for directing a regulatedblast upwardly through an intermediate compartment for deflecting thelighter particles passing therethrough.

15. Apparatus for grading granular material according to the size of theparticles composing same, comprising a distributing disk having a plainupper surface unobstructed and entire extent, means of feeding thematerial on the disk in the form of a thin sheet, the upper surface ofthe disk having a covering hindering the free sliding action butinducing rolling action of the particles, means for rotating the disk,and a plurality of concentrically arranged annular compartments spacedat different distances from the periphery of the disk for separatelycollecting'the particles of varying size discharged therefrom.

In testimony whereof, I sign my name.

F. H. CURTIS, JOHN D, Emerson.

freely exposed throughout its

